The present technology builds on, and extends, technology disclosed in other patent applications by the present assignee. The reader is thus directed to the following applications that serve to detail arrangements in which applicants intend the present technology to be applied, and that technically supplement the present disclosure:
application Ser. No. 61/110,490, filed Oct. 31, 2008;
application Ser. No. 12/271,692, filed Nov. 14, 2008 (now U.S. Pat. No. 8,520,979);
application Ser. No. 12/271,772, filed Nov. 14, 2008 (published as US20100119208);
application Ser. No. 61/150,235, filed Feb. 5, 2009;
application Ser. No. 61/157,153, filed Mar. 3, 2009;
application Ser. No. 61/167,828, filed Apr. 8, 2009;
application Ser. No. 61/169,266, filed Apr. 14, 2009; and
application Ser. No. 61/176,739, filed May 8, 2009.
The disclosures of these documents are incorporated herein by reference.
In one aspect, this specification concerns techniques for recognizing an image (or a video) as one of many stored in a database. The techniques can also be used for recognizing objects in images.
A basic concept behind many of these techniques is representing an image (or object) in terms of simple features that are either invariant to geometric transformations, change of view, noise, occlusions, background, luminance and lighting changes, or that vary slowly with these effects. One such representation is the 3D Color Histogram (c.f., Swain and Ballard, “Color Indexing,” International Journal of Computer Vision, 7(1):11-32, 1991).
Color histograms can be computed relatively quickly and have been widely used for recognition and indexing tasks. However, traditional color histograms suffer from a variety of shortcomings, such as sensitivity to brightness, contrast and luminance changes, and change in illumination.
Aspects of the present technology concern extension of color histogram concepts to create simple representations that are less sensitive to such effects. In addition, simple matching techniques are disclosed, based on histogram parameters and set theory, to provide better robustness under geometric transformations. Also detailed are techniques using histogram representations for quick database search and reduction of search space.
The detailed technology is well suited for operation on mobile devices or embedded systems, mainly due to their simplicity and speed.
The foregoing will be more readily apparent from the following detailed description, which proceeds by reference to the accompanying drawings.